The Transportation Services Index (TSI), created by the US Department of Transportation (DOT), Bureau of Transportation Statistics (BTS), measures the volume of freight and passengers moved monthly by the for-hire transportation sector in the United States.

BTS produces three indexes: a freight index, a passenger index, and a combined index. The indexes incorporate monthly data from multiple for-hire transportation modes.

The TSI index, which is seasonally adjusted, combines available data on freight traffic, as well as passenger travel, that have been weighted to yield a monthly measure of transportation services output.

In 2020, the Freight Transportation Services Index (TSI), which measures the volume of for-hire freight services in the United States, fell about 11 points from February to April of 2020, but by January 2021 was back to a volume similar to before the pandemic.

The Passenger TSI, which measures the volume of for-hire passenger services in the United States, fell 123 points from February to April of 2020, and recovered only 42 points by January 2021.

The Passenger TSI includes local mass transit, intercity passenger rail, and passenger air transportation. The Freight TSI includes for-hire trucking, freight railroad services, inland waterway traffic, pipeline movements, and air freight.